Ok, for those who don't know about this boss, I'll explain first.
Normally a group will engage this boss in a long balcony.
When someone aggro the boss, he'll mount up on his blue proto-drake and fly away, he'll also calling 8-10 elite adds ( pack of 2 ) spreading on balcony, you'll have to fight to get harpoons and to get to harpoon launchers at the end of balcony/
During your way to harpoon launchers, there'll be more adds that keep spawning, and also Skadi's drake will keeps breathing frostfire on the ground too.
But there's a way to get to the harpoons launcher without any fight and you won't have to worry about his drake's frostfire if you just run into building and fight adds inside there.
This will also makes you kill adds faster if you have good AE DPS.
Here's how to do it.
Aggro the boss ( Skadi ) and run back to the previous room ( 2nd boss, Gortok's room ), the fight will reset.
It'd take like 30-60 seconds before Skadi respawn, you and your group can just run to the harpoon launcher while he hasn't spawned.
Now you're at harpoon launchers without any fight
Your group should enter the building then have a DPS go aggro the boss and the rest AE all adds down, you don't have to worry about frostfire breath anymore. You'll also have to fight less spawning adds because you get there faster.